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Employee Defined Benefit Obligations - Additional Information (Detail) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 CAD ($) | Dec. 31, 2018 CAD ($) yr Trustee | Dec. 31, 2017 yr
Disclosure of defined benefit plans [line items] |  |  |
Number of employer-appointed trustee | Trustee |  | 4 |
Percentage of plans' assets invested in mutual funds and exchange-traded funds or held in cash |  | 50.00% |
Percentage of plans' assets held in annuity policies |  | 25.00% |
Weighted average duration of defined benefit obligation | yr |  | 16 | 15
Defined benefit pension plans contribution [member] |  |  |
Disclosure of defined benefit plans [line items] |  |  |
Amount expected to contribute to pension plan by company | $ 23.3 |  |
Defined benefit obligation [member] |  |  |
Disclosure of defined benefit plans [line items] |  |  |
Past service cost |  | $ 10.5 |
Defined benefit obligation [member] | Continuing Operations1[member] |  |  |
Disclosure of defined benefit plans [line items] |  |  |
Past service cost |  | 4.7 |
Defined benefit obligation [member] | Discontinued operations [member] |  |  |
Disclosure of defined benefit plans [line items] |  |  |
Past service cost |  | $ 5.8 |

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- Definition The estimate of the expected contributions to be made to a defined benefit plan for the next annual reporting period. [Refer: Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 147 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_147_b&doctype=Standard -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 148 -Subparagraph d -Clause iii -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_148_d_iii&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from past service cost. Past service cost is the change in the present value of the defined benefit obligation for employee service in prior periods, resulting from a plan amendment (the introduction or withdrawal of, or changes to, a defined benefit plan) or a curtailment (a significant reduction by the entity in the number of employees covered by a plan). [Refer: Net defined benefit liability (asset); Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 141 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_141_d&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The weighted average duration of a defined benefit obligation. [Refer: Weighted average [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 147 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_147_c&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition Number of employer appointed trustee. + References No definition available. + Details
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- Definition Percentage of plan asset in annuity policies. + References No definition available. + Details
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- Definition Percentage of plan asset in securities or held in cash. + References No definition available. + Details
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